Electronic mailboxes reside on electronic mail (email) servers and are used to store email messages. Electronic mailboxes are connected to the Internet to enable users to send and receive incoming and outgoing email messages. These mailboxes may also be extended to deliver email to mobile wireless communication devices via wireless networks. In the case of a corporation, electronic mailboxes are typically located on email servers at the corporation. On the other hand, mailboxes for small businesses or individuals are typically located on Internet service provider (ISP) email servers.
Mail user agents (MUAs) are applications which use a technique called polling to relay messages from the email server to the mail program at a user's computer or mobile wireless communications device. A MUA is a program running either on a user's personal computing device (mobile or stationary), or on a shared email relay server that checks for new mail on behalf of a multitude of such users. More particularly, polling is the retrieval of incoming messages from other users at the mail server and delivery of these messages to the user's mailbox.
One particularly advantageous email retrieval system is disclosed in U.S. Patent Pub. No. 2006/0293032 to Clarke et al., which is assigned to the present Assignee. This system includes at least one wireless communications device and at least one email server for storing email messages for the at least one wireless communications device. The system further includes an email relay server for detecting a new email message on the at least one email server and, based thereon, sending a short message service (SMS) notification with a unique message identifier (ID) of the new email message to the at least one wireless communications device. Moreover, the at least one wireless communications device detects the SMS notification and sends an email retrieval request to the email relay server instructing the email relay server to retrieve the new email message based upon the unique message ID.
One potential difficulty in detecting new email messages on email servers is that as the number of system users grows, so too does the number of mailboxes that the MUA will have to poll for email messages. As such, it may be desirable in certain applications to provide efficient approaches for scheduling polling operations to reduce over-utilization and/or under-utilization of polling resources at any given time.